Answer:
I am an insect half of my name is another insect. I am similar to the name of a famous band.
A man who was outside in the rain without an umbrella or hat didn't get a single hair on his head wet. Why?
I am not a toy though many use me for pleasure. I have a butt but I cannot poo.
Two in a whole and four in a pair. Six in a trio you see. Eight's a quartet but what you must get is the name that fits just one of me.
In all the world none can compare I am a tiny weaver my deadly cloth so silky and fair.
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.